If you dig in dirt for a living, using a dull shovel is like carving a turkey with the back of a knife – you are not going to get very far and you are going to get really tired while you’re not getting very far. Anything that will be used for digging or edging should get a sharp edge.
The tools at the store have dull edges to keep the blood on the floor in front of the tool rack to a minimum. You will be amazed, and I mean really amazed, at how much easier you can dig with a sharp shovel.
The more gravely the soil, the faster your sharp edge will wear down. You can easily maintain a sharp edge with a file (see below).
The easiest way to sharpen a shovel is to take it down to the basement (or maybe yours is in the garage) and flip the switch on the old grinder. Don’t forget the safety glasses – sparks are going to fly all over the place.
What if you don’t have a grinder? You have a couple of options. First, you probably have a neighbor who has one. You can probably guess which neighbor this is without too much help from me.
Second, anyone who sharpens mower blades (that is, anyone who services mowers) will be able to sharpen your shovel.
Third, use a file. A file works perfectly fine, and you will want one around anyway for keeping the edge sharp, but this method does take some heavy duty elbow grease to put on that initial sharp edge. (It’s easy to KEEP a shovel sharp with a file, after the initial sharpening on a grinder, though.) The file you need is 10″ or 12″ mill single cut bastard file. How’s that for an oddly named thing? A mill file has flat sides, and a bastard file has relatively coarse ridges that can file metal. They’ll know exactly what it is down at the hardware store.
File downwards, away from the handle.
Whether you use a file or grinder, only sharpen the beveled (angled) side of the blade. If you don’t see a bevel (and many digging tools come with a dull, rounded blade edge), just sharpen the front side. You can use the grinder to start and then finish with the file.
By the way, a spade has a flat blade and a flat edge. A shovel has a rounded blade and has a point. They both need to be sharp.
This is going to make your gardening life so much easier, you’re not going to want to stop sharpening – go after those hoes and hand trowels next.